In 2016 Professor Niall Herity recommended that the hours be increased as he turned down calls for a second interventional lab at the hospital.
A national review is now underway while a mobile unit has been in place at University Hospital Waterford since October of last year.
Speaking at a meeting of the Oireachtas Health Committee, Sinn Fein's David Cullinane raised the matter with Minister Simon Harris.
"It's 20 months since Prof. Herity made his recommendation, and not one single minute of additional time has been put in place," he said.
"What we're hearing is that there are difficulties in relation to recruitment, but why does it take so long for that information to get to us, and to patients and why would it take 20 months for this to go on with no resolution. It's breathtaking."
The Health Minister granted another six week extension to the Cath Lab last month, and said he shared frustrations over the delay.
"I would rather to be able to provide the additional hours which Prof. Herity had recommended in his report and which we have funded, so that the existing lab could be opened for more hours."
Simon Harris said there's aspects of the Herity Report that are beneficial for Waterford, although he recognised that the lack of 24/7 interventional care remains a source of major concern.
